Now, several million people around world are suffering from hearing impediment, a lot of people among them do not recognize their hearing impediment. Loss of hearing may be caused by several factors including an age, a health, a job, an injury and a disease. The loss of hearing reduces quality of life, deteriorates relationship and obstructs the getting a job. Recently, people who have difficulty in hearing are increased caused by using sound appliances, increasing a percentage of old people and noise environment, thereby demand for a hearing aid is rapidly increased and development of the hearing aid with high performance capable of applying various noise environment is accelerated.
A fitting operation is implemented on a common hearing aid such that the hearing aid provides optimal sound in accordance with a user of the hearing aid. Heretofore, a hearing test is performed prior using additional hearing tester and then the fitting operation is implemented. And, an ordinary seller of hearing aids implements the fitting operation using the hearing tester at an agency on the basis of hearing data which was measured by the hearing tester. As shown in FIG. 1, operations such as a gaining per channels, a compress rate, a noise deduction, a feedback elimination are implemented by a complex program (P).
It cannot consider characteristics of user's ears and the hearing aid that the user's hearing ability is measured by an additional hearing tester to use as hearing measurement information in the fitting operation. Because the fitting is implemented on the basis of hearing data measured by additional hearing tester in accordance with a standard mode in spite that user's ears and a hearing aid have inherent sound characteristics. A fitting is implemented without applying sound around real circumstance because the fitting operation is usually implemented at a quiet agency. Therefore, it is impossible to accept optimal sound through the hearing aid. The following patent discloses fitting on the basis of user's hearing characteristics, however, the hearing test is implemented without hearing aid on. Therefore, it cannot be achieved that hearing test and fitting operation are implemented easily and accurately with considering user's hearing ability and a variation of environment.